Modern surgical techniques often require holes or channels to be cut into bone, teeth or soft tissue, for various reasons. Holes may be drilled in bone to receive screws, sutures or bone anchors enabling anchorage of implants or reattachment of ligaments or tendons. Ordinarily, surgical drills can be employed which utilize a motor (often an air motor) and a drill bit of the desired length and diameter. However, because of the proximity of other tissue or prosthetic materials, it often becomes difficult to appropriately orient a surgical drill and drill bit so that the desired bore can be formed in tissue. Dental drills are available, of course, but have generally very short bit lengths.
U.S. Pat. No. 5,330,468 (Burkhart) proposes a drill mechanism for arthroscopic surgery in which a rotating pin of nitinol is caused to emerge from a gently bent aiming tube, drill through a thickness of bone, and then be received in an appropriately positioned receiving tube. The device itself is somewhat bulky. Another device using nitinol pins or probes is shown in U.S. Pat. No. 4,926,860 (Stice et al.). Here, a needle or other probe of nitinol may be received in a curved cannula to deliver the end of the probe to the desired location. The probe is then advanced through the cannula and exits from the cannula end in a straight orientation.
If a nitinol pin, as shown in the previously mentioned U.S. Pat. No. 5,330,468, is bent through a sharp angle and rotated at high speed, the pin becomes work hardened at the area of the bend due to its constant flexing during rotation. The superelastic characteristic of the pin in that area is reduced, and the pin can readily break. Nitinol wire drills in which a nitinol pin is rapidly rotated in a sharp bend, hence, have not become commercially successful.